Hypoparathyroidism results from reduced secretion of parathyroid hormone by the parathyroid glands. It results in hypocalcemia.
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Epidemiology
Hypoparathyroidism has an estimated prevalance 37 per 100,000 person-years and incidence of 0.8 per 100 000 person-years. It carries no increased risk of mortality. The majority of cases are due to complications from anterior neck surgery.4
Clinical presentation
- tetany: peripheral paresthaesia, carpopedal spasm, seizures
- emotional lability, depression and anxiety, psychosis
- short stature
Pathology
There are a number of causes of hypoparathyroidism 1:
- iatrogenic, e.g. post parathyroidectomy or thyroidectomy
- congenital absence of the parathyroid glands, which may be syndromic in thymic aplasia, or 22q11.2 deletion syndrome (a.k.a. DiGeorge syndrome)
- familial, e.g. autoimmune polyendocrine syndrome type 1
- idiopathic (probably autoimmune-mediated destruction)
Markers
- parathyroid hormone (PTH) level: low
- serum phosphate level: high
- serum calcium level: low
Radiographic features
- musculoskeletal 2,3
- focal (~25%) and generalized (~10%) osteosclerosis
- dense metaphyseal bands
- skull vault thickening 2
- diffuse idiopathic skeletal hyperostosis-like changes
- subcutaneous calcification (around shoulders and hips)
- CNS
- intracranial calcifications: most commonly basal ganglia but also subcortical white matter, corona radiata and thalamus
- head and neck